As any golfer knows, it is typical for golf courses to remain open and for play to continue as long as there is sufficient daylight. Most courses also have special rates for twilight play, as it is understood that the golfer must try to finish a round as daylight is running out, and may not be able to finish at all as it can become too dark to play before the round can be finished. Under such conditions, a golf ball, which is slightly more than one and one half inches across, can be very difficult to see at a distance and the possibility of losing a ball in the course of play is greatly increased.
Prior art attempts to overcome this problem have included several variations, making use of different light sources, such as electric lighting elements, lightsticks, as well as attempts in which photostorage material is mixed into the ball's cover material.
In the case of prior art making use of electric lighting elements, such as disclosed in U.S. Pat. No. 6,257,995, complex electrical circuits and switches, as well as batteries and LEDs are enclosed within the ball's core, inside an outer translucent shell. Such electrical elements create the problem of uneven weight distribution, which can affect the flight properties of the ball, as well as affecting the compression characteristics when hit with a golf club. Another problem is the fragile nature of electrical circuits, batteries and lighting elements, which when hit by the severe impact of a golf club, can be rendered inoperable.
Other prior art, such as disclosed in U.S. Pat. No. 4,878,674, includes the use of separate, cylindrical lightsticks, which are activated, then inserted through a hole drilled through the core of a translucent golf ball. This example of prior art would seem to provide adequate light for its purpose. However, due to the cylindrical shape of the lightsticks, weight distribution is necessarily uneven, and performance of these golf balls is severely impaired, traveling slightly more than half the distance of a standard, non-luminescent, golf ball hit with the same club. Another problem presented by this prior art is that a separate lighting element is utilized, first activated, then inserted into the ball. Thus, the lighting element is not a self contained structural component of the ball itself, which diminishes distance and flight characteristics.
Another example of prior art makes use of photostorage materials, mixed into the cover, and outer layer materials, such as disclosed in U.S. Pat. No. 5,330,195. This prior art is able to create a ball which is of standard size and weight, with performance characteristics similar to standard golf balls. However, the energy required to power the photostorage material is not contained within the ball, requiring the use of a flashlight or similar device to first charge the photostorage material before use. Thus the light source utilized is not self powered.
Thus, there remains a need for a luminescent golf ball with a self-contained and self-powered lighting device to be made more visible in low light conditions, which complies with the United States Golf Association (“USGA”) rules and regulations for golf ball size and weight, and having with general performance characteristics similar to standard, non-luminescent, golf balls.